Vehicle body closure members, such as tailgates, are typically pivotally mounted between body side panels forming the pillars at the rear of the vehicle. The tailgate typically pivots about a hinge axis between a horizontal, open position and a vertical, closed position. Some tailgate mounting assemblies include a counterbalancing hinge assembly for assisting movement of the tailgate and counterbalancing the weight of the tailgate during opening and closing movements.
The tailgate counterbalancing hinge assembly often includes a torque rod that is grounded on one end to the vehicle's tailgate and on the other end to the vehicle so that the torque rod is twisted as the tailgate is moved between open and closed positions.
Although torque rod based tailgate counter balancing hinge designs reduce the effort required to raise and lower a tailgate by storing energy in the twisting of the torque rod during opening/lowering of the tailgate, because of the residual kinetic energy stored in the tailgate, the tailgate, when free falling, can cause objectionable impact on the supports straps or on a vehicle operator. Indeed, because a tailgate can be heavy and hard to lift when being closed, it can drop down quickly when being opened, and thus cause injury to a vehicle operator. The present invention solves these problems by de-accelerating the tailgate and having it come to a gradual stop at the open position, reducing possibility of operator injury or the gate crashing down on check straps that may be mounted to the vehicle box and that keep the tailgate from over traveling.